Auto-instrumentation for OpenAI-compatible Chat Completions endpoints via Req. Works for OpenAI proper (api.openai.com), Azure OpenAI, and the OpenAI-compatible AWS Bedrock endpoint (bedrock-*.api.aws).

Wraps a Req request in an OpenTelemetry LLM span tagged with GenAI semantic-convention attributes. No span code at the call site.

Usage

Req.new(
  method: :post,
  url: "https://api.openai.com/v1/chat/completions",
  json: %{model: "gpt-4", messages: [...], tools: [...]},
  headers: [{"authorization", "Bearer ..."}]
)
|> Impact.Instrumentation.OpenAI.request()

Detects the path /chat/completions (with or without a leading version segment). Non-matching URLs fall through to plain Req.request/1.

What's captured

Request:

• gen_ai.system — "openai" / "aws.bedrock" / "azure" depending on host
• gen_ai.provider.name — same
• gen_ai.operation.name — "chat"
• gen_ai.request.model
• gen_ai.request.max_tokens / temperature / top_p
• gen_ai.input.messages — JSON of [{role, content}, ...]
• gen_ai.system_instructions — JSON of system message contents

Response:

• gen_ai.response.id / gen_ai.response.model
• gen_ai.usage.input_tokens / output_tokens / total_tokens
• gen_ai.response.finish_reasons
• gen_ai.output.messages — JSON of [{role, content}]
• gen_ai.tool.names — csv of names when finish_reason="tool_calls"